1 /* DooM2D: Midnight on the Firing Line
2 * coded by Ketmar // Invisible Vector <ketmar@ketmar.no-ip.org>
3 * Understanding is not required. Only obedience.
5 * This program is free software: you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation, either version 3 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program. If not, see <http://www.gnu.org/licenses/>.
22 #define SEARCH_RADIUS (4)
23 #define MIN_ALPHA (0.05)
25 uniform sampler2D texLMap; // light texture of lightTexSize
26 uniform sampler2D texBg; // background
27 uniform sampler2D texOcc; // occluders
28 uniform vec2 lightTexSize;
29 uniform vec2 mapPixSize;
30 uniform vec4 lightColor;
31 uniform vec2 lightPos;
34 bool hasLight (in vec2 txo, in float pixelStep) {
37 for (int dy = SEARCH_RADIUS*2; dy > 0; --dy) {
38 for (int dx = SEARCH_RADIUS*2; dx > 0; --dx) {
39 if (texture2D(texLMap, txc).a > MIN_ALPHA) return true;
47 float pxs = pixelStep*(SEARCH_RADIUS*2);
49 vec2 txcld = vec2(txo.x-pxs, txo.y+pxs);
50 vec2 txcru = vec2(txo.x+pxs, txo.y-pxs);
52 vec2 txcu = vec2(txo.x, txo.y-pxs);
53 vec2 txcd = vec2(txo.x, txo.y+pxs);
54 vec2 txcl = vec2(txo.x-pxs, txo.y);
55 vec2 txcr = vec2(txo.x+pxs, txo.y);
56 vec2 txcrStep = vec2(pixelStep, -pixelStep);
57 float pst2 = pixelStep*2;
58 for (int d = SEARCH_RADIUS; d > 0; --d) {
59 if (texture2D(texLMap, txclu).a > MIN_ALPHA) return true;
61 if (texture2D(texLMap, txcld).a > MIN_ALPHA) return true;
65 if (texture2D(texLMap, txcru).a > MIN_ALPHA) return true;
68 if (texture2D(texLMap, txcrd).a > MIN_ALPHA) return true;
71 if (texture2D(texLMap, txcu).a > MIN_ALPHA) return true;
73 if (texture2D(texLMap, txcd).a > MIN_ALPHA) return true;
76 if (texture2D(texLMap, txcl).a > MIN_ALPHA) return true;
78 if (texture2D(texLMap, txcr).a > MIN_ALPHA) return true;
85 //gl_FragCoord: in background
88 vec2 vTexCoord0 = gl_TexCoord[0].xy; // in light texture (texLMap)
89 vec2 btxy = gl_FragCoord.xy/mapPixSize;
90 vec2 ocxy = vec2(btxy.x, 1.0-btxy.y);
93 if (texture2D(texOcc, ocxy).a <= 0.75) discard; // empty space
95 // occluder hit; look for light in 8px radius
96 float pixelStep = 1.0/lightTexSize.x;
97 if (!hasLight(vTexCoord0, pixelStep)) discard;
99 vec4 bcolor = texture2D(texBg, btxy);
100 // light is y-mirrored
101 vec2 ourpos = vec2(gl_FragCoord.x, mapPixSize.y-gl_FragCoord.y-1.0);
102 // distance from this point to light origin
103 float lit = clamp(1.0-(distance(ourpos, lightPos)/(lightTexSize.x/2.0)), 0.0, 1.0);
104 lit = smoothstep(0.1, 1.0, lit);
105 if (lightColor.a == 0.0) {
106 color = bcolor*vec4(vec3(1.0), lit);
108 color = lightColor*lit;
112 gl_FragColor = color;